Modern cosmetic cleansing products for skin and hair, such as, for example, shower baths and hair shampoos, consist essentially of                water as the most important solvent,        surfactants,        viscosity regulators for thickening the formulation,        solubility promoters (solubilizers) for water-insoluble substances,        perfume oils,        preservatives and        active ingredients for the care of skin and hair, such as, for example, refatting agents.        
Typical surfactants in body cleansing compositions are of anionic, amphoteric and zwitterionic structure. The anionic surfactants include, in particular, the salts of various cations (sodium, ammonium or others) of lauryl sulfate, lauryl ether sulfate, myristyl ether sulfate etc. The zwitterionic surfactants used are, inter alia, cocamidopropylbetaine or cocoamidopropylsultaine. Amphoteric surfactants are, in particular, amphoacetates, such as sodium cocoamphoacetate or disodium cocoamphodiacetate.
Typical thickeners used according to the prior art are NaCl, low molecular weight nonionic surfactants, such as coconut fatty acid monoethanolamide/diethanolamide and laureth-3, or polymeric, high molecular weight, associative, highly ethoxylated fatty derivatives, such as, for example, polyethylene glycol(9000)-hydrogenated glycerol palmitate.
Within the meaning of the present invention, solubilizer or solubility promoter is the term used to refer to a substance which is able to dissolve water-insoluble compounds in aqueous systems to give as clear a solution as possible. According to generally accepted opinion, in this process, micelles are formed, in whose liquid-crystalline structure the hydrophobic substances are integrated. The formation of a “microemulsion”, i.e., a thermodynamically stable mixture of water (aqueous solution), an oil (substance immiscible with water) and a solubilizer/solubility promoter is optimal. Typical solubilizers are ethoxylated fatty derivatives.
Perfume oils are generally added to the formulations to improve the olfactory properties. Acceptance by the consumer plays the most important role here. In addition, it is possibly advantageous to mask the intrinsic odors of raw materials used with perfume oils.
Preservatives are used for microbiological stabilization. In the case of contamination, these ingredients (i.e., preservatives) should prevent microbial growth and optionally also kill germs. Preservatives are described in detail and regulated in official regulations (e.g., EU Cosmetics Ordinance).
Typical care additives are ethoxylated glycerol fatty acid esters, such as, for example, polyethylene glycol(7) glyceryl monococoate, or cationic polymers, such as, for example, polyquaternium-7. During skin cleansing, besides the lipophilic dirt, endogenous lipids are also washed away by the surfactants used. This effect is often perceived as unpleasant; that is the skin feels rough and harsh. The skin is also referred to as “dry”, although what is meant here is the absence of fat.
So-called refatting agents are added to body cleansing compositions so that the described defatting process is lessened. As a result, on the one hand, the washed-off fat can be replaced by the refatting agent, but on the other hand, the defatting effect of the formulation per se can also be lessened through the use of the refatting agent.
From a formulation point of view, it is difficult to use emollients (cosmetic oils), such as, for example, isopropyl myristate (TEGOSOFT M®), for this purpose because these oils have to be solubilized in a complex manner. More customary refatting agents are therefore relatively hydrophilic products, such as, for example, polyethylene glycol(7) glyceryl monococoate (TEGOSOFT GC®) which are already stabilized through the excess of the cleansing surfactants. Analysis of a product database which gathers worldwide product innovations in consumer markets (“Global New Products Database”: Mintel) revealed that 29% of all skin cleansing formulations in the European market in the period of investigation (9/05-9/06) comprised polyethylene glycol(7) glyceryl monococoate.
It is assumed that the refatting process takes place upon rinsing off the formulation after the actual washing. During the rinsing process with water, the solution present is diluted until the so-called CMC (critical micelle concentration) is reduced. With the release of the micelle components (the lipophilic refatting agents, the surfactants and solubilizers), the refatting agents become insoluble again. These lipophilic substances (both endogenous lipids and also emollients/cosmetic oils) precipitate out and attach to the skin.
Besides the cleansing effect, the requirements of the finished formulation thus include a creamy foam, protection against the drying out of the skin and a good care performance. The basic requirements for the individual constituents include good skin compatibility and processability. It would therefore be advantageous if as many of the requirements for a cosmetic formulation as possible could be satisfied by the fewest possible toxicologically acceptable and universally usable constituents.
DE-A 40095533 describes foam-suppressed nonionic surfactant mixtures comprising 20 to 98% by weight of an alkyl polyglycoside and 80 to 2% by weight of a polyglycol ether. The latter component is added to the surfactant mixture on account of its foam-suppressing effect. The polyglycol ethers preferably used also include alkyl ethers of propoxylated fatty alcohols. However, polypropylene glycol(3) myristyl ether is not explicitly mentioned in the entire printed specification. The liquid washing compositions produced using the prior art disclosed surfactant systems also comprise a large number of additional components, and there is no indication at all that the polyglycol ethers used perform further functions in the particular washing composition formulation besides their foam-suppressing effect. Furthermore, the washing composition systems specified by way of example differ from the formulations according to the invention by virtue of their comparatively low water content, at about 35% by weight.
EP-A 0459769 discloses cleansing compositions, in particular soap bars, which exhibit reduced softening and increased gentleness. The described compositions comprise alkali metal salts of higher fatty acids in an amount greater than 25% by weight, 1-50% by weight of a further surfactant, 1-15% by weight of a free fatty acid, and 1-15% by weight of a component which reduces softening. These components also include the alkyl ethers of alkoxylated fatty alcohols, such as, for example, polypropylene glycol(3) myristyl ether. However, further modes of action are not specified. It is also obvious that the disclosed cleansing compositions differ significantly from the compositions according to the invention on account of their very low water content (about 10% by weight).
EP-A 1407761 describes aqueous alcoholic compositions, for example disinfection solutions, which comprise alcohol and water in a weight ratio of from 60:40 to 100:0, and between 0.5 and 8% by weight of a thickener system comprising at least one emulsifier. A large number of further constituents may be present in the aqueous-alcoholic compositions, including emollients, such as polypropylene glycol(3) myristyl ether. Even though the specification indicates that, although a thickener system may be responsible for the stability and consistency of the described compositions, emollients could also influence the viscosity and stability of the compositions, an effect cannot be deduced from the experimental data. Also, when evaluating the described effects, the sometimes extremely high alcohol content of the investigated systems must not be disregarded.
Finally, U.S. Pat. No. 7,087,221 discloses aqueous shampoo compositions with improved hair-conditioning properties comprising at least 20% by weight of water, between 5 and 50% by weight of a surfactant and at least 0.05% by weight of a polyalkylene oxide alkyl ether, which should have an HLB value (hydrophilic-lipophilic balance) of less than 10. Polypropylene glycol(3) myristyl ether is not given under the compounds specified by way of example. The large number of possible further components and also the complex test formulations illustrate that in the '221 patent there is also no teaching which could be associated with the object underlying the present invention.
Thus, none of the cited specifications discloses the use of emollients, in particular polypropylene glycol(3) myristyl ether, as viscosity regulator, care active ingredient or solubilizer in aqueous surface-active formulations.